You can download optisystem from the optiwave website itself if you wish to use it. For that matter it would be a trial version and you will be having a 30 day evaluation period and after 30 days your tool would get terminated if you do not buy a license which is very necessary to keep using the tool. It is a licensed software. You can further consult the optiwave support team for further inquiries. I hope you find it helpful.
Thanks and regards
you can download the sogtware from this site only by clicking the downloads link and you would get the trial version of the latest optisystem version that is optisystem 14. As fayiqa said it will be terminated after about 30 days and hence we would suggest you to buy the license in order the optisystem software with no time limit . i would attach a link to download the trial version and if you find it useful you can switch to license version of this software.